Double-layer metamaterial magnetic induction antenna based on coil posture optimization and communication device

Abstract

The application belongs to the technical field of wireless communication, and discloses a double-layer metamaterial magnetic induction antenna based on coil posture optimization and a communication device, which comprises a center magnetic induction annular antenna, inner layer coils distributed on an inner layer spherical surface, the inner layer spherical surface being a spherical surface with the center of the center magnetic induction annular antenna as a spherical center, the inner layer coils being uniformly distributed on a selected inner layer actual distribution area on the inner layer spherical surface, outer layer coils distributed on an outer layer spherical surface, the circuit parameters of all the outer layer coils and the inner layer coils being the same, the outer layer spherical surface and the inner layer spherical surface sharing the spherical center and having a radius greater than that of the inner layer spherical surface, the outer layer coils being uniformly distributed on a selected outer layer actual distribution area on the outer layer spherical surface, and the total mutual inductance of the inner layer coils and the total mutual inductance of the outer layer coils being the same. The application can amplify the magnetic field generated by the center magnetic induction annular antenna in multiple stages by only arranging the inner and outer two layer coil arrays, effectively improves the communication performance of the antenna, and has a simple structure and is easy to implement.

Description

Technical Field

[0001] This invention belongs to the technical field of wireless communication technology, and more specifically, relates to a dual-layer metamaterial magnetic induction antenna and communication device based on coil attitude optimization. Background Technology

[0002] Magnetic induction communication technology, with its unique advantages such as absence of multipath interference and insensitivity to the Doppler effect, has shown great potential in wireless communication in extreme environments such as underwater, underground, and sandy soil. However, with the rise of emerging applications such as the Internet of Things, extremely stringent limitations have been placed on the size of communication devices. Moreover, when the signal wavelength is long, antenna efficiency drops sharply, resulting in severely limited communication distance.

[0003] To overcome this bottleneck, researchers have generally turned their attention to metamaterial antenna technology. Metamaterial antenna technology, by designing the shape, size, and arrangement of the antenna's internal structure, can "programmably" control the material's equivalent permittivity and permeability, and even achieve exotic phenomena such as negative refraction and perfect lenses, thereby obtaining electromagnetic properties not found in natural materials and breaking through the performance limitations of traditional antennas. For example, the Chinese patent application "CN223378446U - Antenna and Electronic Equipment" integrates planar metamaterial units inside a resonant ring to generate properties such as negative permeability. However, its performance heavily depends on the precision of the metamaterial structure at the subwavelength scale, requiring extremely high precision in processes such as PCB etching, and exhibiting low tolerance. Hongzhi Guo of the State University of New York discovered that magnetic induction antennas surrounded by metamaterial shells can enhance the magnetic field around MI transceivers. They also proposed and fabricated reconfigurable active metamaterial antennas to further improve communication range, but this approach increases the complexity of metamaterial antennas.

[0004] In summary, while seeking to improve performance, existing technologies often sacrifice ease of implementation and practicality in engineering, thus falling into the dilemma of high performance and high complexity.

[0005] Therefore, how to enhance the performance of antenna magnetic induction communication in a simpler and easier-to-implement way is a technical problem that urgently needs to be solved. Summary of the Invention

[0006] In view of the above-mentioned defects or improvement needs of the prior art, the present invention provides a double-layer metamaterial magnetic induction antenna and communication device based on coil attitude optimization, the purpose of which is to enhance the antenna magnetic induction communication performance in a simpler and easier-to-implement manner.

[0007] To achieve the above objectives, the present invention proposes the following technical solution.

[0008] According to a first aspect of the present invention, a dual-layer metamaterial magnetic induction antenna based on coil attitude optimization is provided, comprising: Central magnetic induction loop antenna; The inner layer coils are distributed on the inner spherical surface. The internal circuit of each inner layer coil is an RLC series resonant circuit. The inner spherical surface is a sphere with the center of the central magnetic induction loop antenna as its center. The inner layer coils are uniformly distributed on the inner spherical surface in the selected inner layer actual distribution area. The outer coils are distributed on the outer spherical surface. All outer coils and inner coils have the same circuit parameters. The outer spherical surface and the inner spherical surface share the same center and the outer spherical surface has a larger radius than the inner spherical surface. The outer coils are evenly distributed on the selected outer layer distribution area on the outer spherical surface. The total mutual inductance of the inner coils is the same as that of the outer coils.

[0009] Optionally, the inner coils are evenly distributed on multiple parallel circles of the inner sphere, and the outer coils are evenly distributed on multiple parallel circles of the outer sphere. Each pair of adjacent inner coils on the same parallel circle corresponds to one outer coil, and the distance between the outer coil and the center of its corresponding two inner coils is the same.

[0010] Optionally, the inner spherical surface has two actual distribution regions located on both sides of the plane where the central magnetic induction loop antenna is located, and the two actual distribution regions have the same inner coil distribution; the outer spherical surface has two actual distribution regions located on both sides of the plane where the central magnetic induction loop antenna is located, and the two actual distribution regions have the same outer coil distribution. The inner layer actual distribution area and the outer layer actual distribution area are both located within the effective space area. The effective space area is the space area enclosed by a conical surface with the center of the sphere as the vertex and the radius of the sphere perpendicular to the plane where the central magnetic induction loop antenna is located as the central axis. The angle between the generatrix of the conical surface and the central circumference is in the range of 50° to 60°.

[0011] Optionally, the coil plane of the inner coil is tangent to the inner spherical surface or perpendicular to the direction of the source magnetic field; the coil plane of the outer coil is tangent to the outer spherical surface or perpendicular to the direction of the source magnetic field, wherein the source magnetic field is the magnetic field generated by the central magnetic induction loop antenna.

[0012] Optionally, it also includes an inner spherical fixing structure and an outer spherical fixing structure, wherein the inner coil is fixed on the inner spherical fixing structure and the outer coil is fixed on the outer spherical fixing structure.

[0013] Optionally, both the inner spherical fixing structure and the outer spherical fixing structure are made of plastic.

[0014] Optionally, both the inner coil and the outer coil are circular PCB boards.

[0015] Optionally, both the inner coil and the outer coil have 1 turn.

[0016] Optionally, the radius of the central magnetic induction loop antenna ranges from 2cm to 3cm, the radius of the inner spherical surface ranges from 4cm to 6cm, and the radius of the outer spherical surface ranges from 6cm to 8cm.

[0017] According to a second aspect of the present invention, a communication device is provided, comprising the above-described dual-layer metamaterial magnetic induction antenna.

[0018] Overall, compared with the prior art, the technical solutions conceived in this invention have the following beneficial effects.

[0019] 1. This invention comprises an inner coil array and an outer coil array surrounding a central magnetic induction loop antenna. The coils in each array are uniformly distributed and have identical parameters. The spatial relationship between the inner and outer coils is optimized to ensure that the total mutual inductance of the inner coils is the same as that of the outer coils. Analysis reveals that when the parameters of the inner and outer coils are identical and their total mutual inductance is also identical, the resonant frequencies of the inner and outer layers are the same (detailed analysis follows). This concentrates the magnetic field energy at the same frequency, resulting in a longer communication distance and better communication performance. This invention only requires two coil arrays (inner and outer layers) to amplify the magnetic field generated by the central magnetic induction loop antenna in multiple stages, effectively improving the antenna's communication performance. Its structure is simple and easy to implement.

[0020] 2. Further, in a specific embodiment, the inner and outer coils are distributed in a parallel circular pattern, with each pair of adjacent inner coils corresponding to an outer coil at an equal distance. This distribution facilitates coil arrangement and ensures that the coil spacing and number of the inner and outer coils are essentially the same. When the circuit parameters of the inner and outer coils are the same, and the coil spacing and number of the inner and outer coils are essentially the same, the total mutual inductance of the inner layer and the total mutual inductance of the outer layer are also essentially the same, thereby making the inner and outer resonant frequencies essentially the same, concentrating the antenna's transmission energy, and thus improving the antenna's communication performance.

[0021] 3. Furthermore, in a specific embodiment, simulation of the spherical antenna model revealed that the coil current near the equator of the sphere (the plane where the central magnetic induction loop antenna is located) is extremely small, indicating that its effect on improving communication performance is negligible. Therefore, removing the coil near the equator of the sphere and retaining the coil within the conical area with an angle of 50° to 60° can maintain a high magnetic field gain while reducing the number of coils by about one-third.

[0022] 4. Further, optimize the coil placement orientation so that the coil plane of the inner coil is tangent to the inner spherical surface or perpendicular to the direction of the source magnetic field; and make the coil plane of the outer coil tangent to the outer spherical surface or perpendicular to the direction of the source magnetic field. The above coil placement orientation can further enhance the induced magnetic field, thereby further enhancing the communication effect. Attached Figure Description

[0023] Figure 1(a) is a magnetic field-frequency curve of a double-layer metamaterial magnetic induction antenna before the two peaks are merged in one embodiment; Figure 1(b) is a magnetic field-frequency curve of a double-peak magnetic induction antenna after merging the two peaks in one embodiment; Figure 2 This is a schematic diagram of the main structure of a double-layer metamaterial magnetic induction antenna based on coil attitude optimization according to an embodiment of the present invention, wherein (a) is a three-dimensional distribution diagram of the coils, and (b) is a top view of (a). Figure 3 This is a physical diagram of the inner layer structure in one embodiment of the present invention, wherein (a) is a physical diagram of the inner layer with the inner layer opened, and (b) is a schematic diagram of the inner layer structure; Figure 4 This is a simulation result diagram of current simulation of a single-layer spherical model of a magnetic induction antenna in one embodiment; Figure 5 This is a schematic diagram of a coil within the area enclosed by a conical surface with an included angle of 54.7°, as shown in one embodiment of the present invention. Figure 6(a) is a graph showing the relationship between the magnitude and frequency of the magnetic field of the antenna when the coil near the equator is not removed in an embodiment of the present invention; Figure 6(b) is a graph showing the relationship between the magnetic field magnitude and frequency of an antenna with coils near the equator removed and the remaining coils arranged uniformly in one embodiment of the present invention. Figure 7 This is a graph showing the relationship between the receiving end voltage and frequency when a single-layer metamaterial magnetic induction antenna and the double-layer metamaterial magnetic induction antenna proposed in this invention are used as transmitting coils in one embodiment. Figure 8 This is a graph showing the relationship between the receiving end voltage and distance when a single-layer metamaterial magnetic induction antenna and a double-layer metamaterial magnetic induction antenna are used as transmitting coils in one embodiment, at the resonant frequency. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0025] In a first aspect, the present invention provides a dual-layer metamaterial magnetic induction antenna based on coil attitude optimization.

[0026] In our previous research, our team discovered that using a coil array to surround a magnetic induction loop antenna can improve its communication performance. Furthermore, setting up two coil arrays, one inner and one outer, with their resonant frequencies being identical, can further enhance the antenna's communication capabilities. However, due to differences in the spacing and number of coils in the inner and outer layers, their resonant frequencies differ, resulting in distinct peak magnetic fields at their respective resonant points. Generally, adjusting the resonant frequency involves adjusting the capacitance within the coils. By adjusting the capacitance of the inner and outer coils, the resonant frequencies of the two layers can be made equal, thus achieving the optimal antenna communication performance. Figure 1(a) shows the magnetic field-frequency curve of the double-peak magnetic induction antenna in one embodiment before the double peaks are combined, and Figure 1(b) shows the magnetic field-frequency curve of the double-peak magnetic induction antenna in one embodiment after the double peaks are combined. When the inner and outer capacitors are not matched, the resonant frequencies of the inner and outer layers are different. The antenna exhibits magnetic field peaks of -61.14 dBA / m and -58.79 dBA / m at 11.91 MHz and 13.61 MHz, respectively. The energy is dispersed and the radiation efficiency is low. After the capacitors are matched, the resonant frequencies of the inner and outer layers are the same, and the double peaks are combined into a single sharp peak at 13.48 MHz. The magnetic field strength is -55.32 dBA / m, and the energy is more concentrated at the same target resonant frequency, resulting in better antenna communication performance.

[0027] However, while adjusting the capacitor can effectively tune the inner and outer layer resonant frequencies to a unified target operating frequency, this relies on the capacitor's high-precision continuous adjustability. In actual antenna manufacturing, even adjustable capacitors cannot achieve such high-precision continuous adjustment. Therefore, although adjusting the capacitor can theoretically tune the inner and outer layer resonant frequencies to the same frequency to effectively enhance the antenna's communication performance, it presents practical difficulties.

[0028] Based on this, the present invention proposes the following technical solution: by designing the spatial structure distribution of the double-layer metamaterial magnetic induction antenna, the inner and outer layers achieve a unified resonant frequency, thereby effectively enhancing the antenna's communication performance. Compared to traditional technologies, this technical solution only requires setting two coil arrays, inner and outer, around the central magnetic induction loop antenna. Its structure is simple, and the inner and outer layers use the same coils. By optimizing their spatial relationship, the resonant frequencies of the inner and outer layers can be adjusted to the same frequency to enhance the antenna's communication performance. Therefore, this technical solution can enhance the antenna's magnetic induction communication performance in a simpler and easier-to-implement manner.

[0029] like Figure 2The diagram shows a schematic representation of the main structure of a double-layer metamaterial magnetic induction antenna based on coil attitude optimization according to an embodiment of the present invention. (a) is a three-dimensional distribution diagram of the coils, and (b) is a top view of (a). Figure 3 The image shown is a physical diagram of the inner layer structure in one embodiment of the present invention, wherein (a) is a physical diagram of the inner layer with the inner layer opened (the central magnetic induction loop antenna is fixed by white foam), and (b) is a schematic diagram of the inner layer structure. The following is in conjunction with... Figure 2 and Figure 3 The antenna structure proposed in this invention will be described.

[0030] In this invention, the dual-layer metamaterial magnetic induction antenna based on coil attitude optimization includes: a central magnetic induction loop antenna; inner layer coils distributed on the inner spherical surface, each inner layer coil having an internal circuit of an RLC series resonant circuit, the inner spherical surface being a sphere with the center of the central magnetic induction loop antenna as its center, the inner layer coils being uniformly distributed in the inner layer actual distribution area on the inner spherical surface; and outer layer coils distributed on the outer spherical surface, all outer layer coils having the same circuit parameters as the inner layer coils, the outer layer sphere sharing the same center with the inner layer sphere and having a larger radius than the inner layer sphere, the outer layer coils being uniformly distributed in the outer layer actual distribution area on the outer spherical surface; the total mutual inductance of the inner layer coils being the same as the total mutual inductance of the outer layer coils.

[0031] The original antenna body is a central magnetic induction loop antenna. This invention sets up an inner coil array and an outer coil array surrounding the central magnetic induction loop antenna. The coils in each array are evenly distributed and have the same parameters. By optimizing the spatial relationship between the inner and outer coils, the total mutual inductance of the inner coils is made the same as that of the outer coils, thereby improving the antenna communication effect. As analyzed above, making the resonant frequencies of the inner and outer layers the same allows the magnetic field energy to be more concentrated at the same frequency. The more concentrated the magnetic field energy, the longer the antenna communication distance and the better the antenna communication effect. Through analysis, it was found that by making the circuit parameters of the inner and outer coils the same, and by adjusting the total mutual inductance of the inner and outer layers to be equal, the resonant frequencies of the inner and outer layers can be made the same. Furthermore, through analysis of the factors affecting the total mutual inductance of the coil array, it was found that it is mainly affected by the spacing between the coils and the number of coils. Therefore, this invention makes the inner and outer coil arrays evenly distributed, which makes it easier to optimize the coil spacing and number, making the total mutual inductance of the inner and outer coils the same, thereby making the resonant frequencies of the inner and outer layers the same, the magnetic field energy more concentrated, and the antenna communication effect better.

[0032] The analysis process is presented below.

[0033] By deriving and analyzing the resonant frequencies of the coil array, the expressions for the optimal resonant frequencies of the inner and outer layers are obtained as follows: (1); In the formula, The optimal resonant frequency for the inner layer. The optimal resonant frequency of the outer layer. The resistances of the inner and outer coils are... For the inner and outer coil inductance, The capacitance of the inner coil. The capacitance of the outer coil. For the first The inner coil and the first Mutual inductance of the outer coils For the m-th inner coil and the... Mutual inductance of the inner coils For the first The outer coil and the first The mutual inductance of the outer coils; M is the number of inner coils, and N is the number of outer coils.

[0034] As can be seen from the above formula (1), the resonant frequencies of the inner and outer layers are related to the structure of the inner and outer coil arrays. By adjusting the structure of the inner and outer coil arrays, the resonant frequencies of the inner and outer coil arrays can be adjusted to make the inner and outer resonant frequencies the same or different. When the resonant frequencies of the inner and outer layers are different, the double-layer metamaterial magnetic induction antenna can exhibit dual resonant frequency characteristics. At this time, the antenna can transmit two kinds of signals through the two resonant frequencies. For example, one transmits information to realize wireless communication; the other transmits energy to realize wireless charging.

[0035] In this invention, to improve communication performance, the inner and outer resonant frequencies need to be tuned to be the same. Based on the above formula (1), the conventional idea is to adjust the capacitance of the inner and outer coils to make the inner and outer resonant frequencies consistent. However, as mentioned above, although adjusting the capacitance can effectively adjust the inner and outer resonant frequencies to a unified target operating frequency, this relies on the high-precision continuous adjustability of the capacitor. In the actual antenna manufacturing process, even adjustable capacitors cannot achieve high-precision continuous adjustment. Therefore, although adjusting the capacitance can theoretically adjust the inner and outer resonant frequencies to the same frequency to effectively enhance the antenna's communication performance, it is difficult to implement in practice.

[0036] Therefore, further analysis of the above formulas by this invention reveals that, when the circuit parameters of the inner and outer coils are the same, as long as the total mutual inductance of the inner coil is made... Total mutual inductance with outer coil If they are the same, then we can obtain .

[0037] Further analysis of the influencing factors of mutual inductance in spherically distributed coils revealed that the mutual inductance between any two coils on a sphere is mainly affected by... The influence of r, where r is the radius of the sphere. The angle between the lines connecting the centers of the two coils to the center of the sphere is given. Therefore, adjusting the spacing between the coils can adjust their mutual inductance. Assuming the coils are evenly distributed, it's easy to optimize the coil array distribution, ensuring the total mutual inductance of the inner coils is the same as that of the outer coils, ultimately achieving... .

[0038] In one embodiment, the inner and outer coils can be distributed according to the following rules: the inner coils are evenly distributed on multiple parallel circles on the inner sphere, and the outer coils are evenly distributed on multiple parallel circles on the outer sphere. Each pair of adjacent inner coils on the same parallel circle corresponds to one outer coil, and the distance between the outer coil and the center of its corresponding two inner coils is the same.

[0039] In the above embodiments, both the inner and outer coils are distributed in a parallel circular pattern, and each pair of adjacent inner coils corresponds to an outer coil at an equal distance. This distribution facilitates the arrangement of the coils and ensures that the coil spacing and number of the inner and outer coils are basically the same. When the circuit parameters of the inner and outer coils are the same and the coil spacing and number of the inner and outer coils are basically the same, the total mutual inductance of the inner layer is also basically the same as that of the outer layer. This results in the inner and outer resonant frequencies being basically the same, making the antenna's transmission energy more concentrated and thus improving the antenna's communication performance.

[0040] In one embodiment, the antenna size can be reduced while maintaining essentially no reduction in antenna communication performance. Specifically, the inner spherical surface has two actual distribution regions located on either side of the plane where the central magnetic induction loop antenna is located, and the two actual distribution regions have the same inner coil distribution; the outer spherical surface has two actual distribution regions located on either side of the plane where the central magnetic induction loop antenna is located, and the two actual distribution regions have the same outer coil distribution; wherein, both the inner and outer actual distribution regions are located within an effective space region, which is the space region enclosed by a conical surface with the center of the sphere as its vertex and the radius of the sphere perpendicular to the plane where the central magnetic induction loop antenna is located as its central axis, and the angle between the generatrix of the conical surface and the central circumference ranges from 50° to 60°.

[0041] A further improvement to the antenna in the above embodiments lies in removing the coils near the equator of the sphere (the plane where the central magnetic induction loop antenna is located) to simplify the structure. For example... Figure 4The image shows the simulation results of current simulation on a single-layer spherical model of a magnetic induction antenna in one embodiment. Simulation of the spherical antenna model reveals that the coil current near the equator of the sphere (the plane where the central magnetic induction loop antenna is located) is extremely small, indicating that its effect on improving communication performance is negligible. Therefore, the coil near the equator can be removed, retaining the coil within the conical area with an angle of 50°~60°. This allows for effective reduction of the antenna size while maintaining essentially no degradation in antenna communication performance. Figure 5 The diagram shown is a schematic of a coil within the area enclosed by a conical surface with an included angle of 54.7°, as per an embodiment of the present invention.

[0042] Figure 6(a) shows the relationship between the magnitude of the magnetic field and the frequency of the antenna when the coil near the equator is not removed in one embodiment of the present invention. Figure 6(b) shows the relationship between the magnitude of the magnetic field and the frequency of the antenna after the coil near the equator is removed in one embodiment of the present invention. It can be seen that after removing the coil near the equator, the magnetic field energy is still highly concentrated at the target frequency, indicating that removing the coil near the equator basically does not affect the communication performance of the antenna.

[0043] In one embodiment, the coil placement orientation can be optimized so that the coil plane of the inner coil is tangent to the inner spherical surface or perpendicular to the direction of the source magnetic field; and the coil plane of the outer coil is tangent to the outer spherical surface or perpendicular to the direction of the source magnetic field; wherein the source magnetic field is the magnetic field generated by the central magnetic induction loop antenna. This coil placement orientation can further enhance the induced magnetic field, thereby further enhancing the communication effect.

[0044] Specifically, the dual-layer metamaterial magnetic induction antenna has a structure for fixing the coils. In one embodiment, the dual-layer metamaterial magnetic induction antenna has an inner spherical fixing structure and an outer spherical fixing structure, which together form a dual-layer structure. The inner layer coil is fixed to the inner spherical fixing structure, and the outer layer coil is fixed to the outer spherical fixing structure. The fixing structure is made of an insulating material, specifically plastic, which has good insulation performance and low cost.

[0045] In one embodiment, both the inner and outer coils are on a circular PCB board with a diameter ranging from 1cm to 3cm. This allows for the integration of an RLC series resonant circuit without occupying excessive space, resulting in a smaller overall antenna size. The values ​​of the capacitor, resistor, and inductor in the RLC series resonant circuit can be determined based on the target frequency.

[0046] In one embodiment, the central magnetic induction loop antenna has 5 turns and a radius ranging from 2cm to 3cm, for example, 2.5cm. Both the inner and outer coils have 1 turn each. The inner spherical radius ranges from 4cm to 6cm, for example, 5cm, and the outer spherical radius ranges from 6cm to 8cm, for example, 7cm. It should be noted that the specific dimensions are flexibly set according to actual requirements. In practical applications, the central magnetic induction loop antenna is directly connected to an AC power supply. Its function is to generate a magnetic field through the alternating power supply that interacts with the inner and outer coils.

[0047] like Figure 7 The diagram shows the relationship between the receiving end voltage and frequency when a single-layer metamaterial magnetic induction antenna and the proposed double-layer metamaterial magnetic induction antenna are used as transmitting coils in one embodiment. DMMI represents the double-layer metamaterial magnetic induction antenna, and MMI represents the single-layer metamaterial magnetic induction antenna. It can be seen that the receiving end voltage of the double-layer antenna is generally higher than that of the single-layer antenna, with its peak voltage reaching 1.8 times that of the single-layer antenna. This indicates that the proposed double-layer metamaterial magnetic induction antenna effectively improves communication performance compared to the single-layer metamaterial magnetic induction antenna.

[0048] like Figure 8 The diagram shows the relationship between the receiver voltage and distance at the resonant frequency when a single-layer metamaterial magnetic induction antenna and a double-layer metamaterial magnetic induction antenna are used as transmitting coils in one embodiment. It can be seen that, at the same communication distance, the receiver voltage of the double-layer antenna is consistently higher than that of the single-layer antenna, and its voltage value is always maintained at more than 1.5 times that of the single-layer antenna. This indicates that, compared to the single-layer metamaterial magnetic induction antenna, the double-layer metamaterial magnetic induction antenna proposed in this invention can effectively improve communication performance.

[0049] Secondly, the present invention also claims protection for a communication device comprising the double-layer metamaterial magnetic induction antenna described above. Specifically, the communication device may be an underwater unmanned aerial vehicle (UAV) or similar device.

[0050] Overall, this invention features an inner coil array and an outer coil array surrounding a central magnetic induction loop antenna. The coils in each array are uniformly distributed and have identical parameters. Optimizing the spatial relationship between the inner and outer coils ensures that the total mutual inductance of the inner and outer coils is the same, resulting in identical resonant frequencies for both layers. This concentrates magnetic field energy at the same frequency, leading to greater communication distance and better communication performance. This invention only requires two coil arrays (inner and outer) to improve antenna communication, and its structure is simple and easy to implement.

[0051] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification. It should be noted that the terms "in one embodiment," "for example," and "again" are intended to illustrate the present invention and are not intended to limit the present invention.

[0052] The above embodiments merely illustrate several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention.

Claims

1. A double-layer metamaterial magnetic induction antenna based on coil attitude optimization, characterized in that, include: Central magnetic induction loop antenna; The inner layer coils are distributed on the inner spherical surface. The internal circuit of each inner layer coil is an RLC series resonant circuit. The inner spherical surface is a sphere with the center of the central magnetic induction loop antenna as its center. The inner layer coils are uniformly distributed on the inner spherical surface in the selected inner layer actual distribution area. The outer coils are distributed on the outer spherical surface. All outer coils and inner coils have the same circuit parameters. The outer spherical surface and the inner spherical surface share the same center and the outer spherical surface has a larger radius than the inner spherical surface. The outer coils are evenly distributed on the selected outer layer distribution area on the outer spherical surface. The total mutual inductance of the inner coils is the same as that of the outer coils.

2. The dual-layer metamaterial magnetic induction antenna as described in claim 1, characterized in that, The inner coils are evenly distributed on multiple parallel circles on the inner spherical surface, and the outer coils are evenly distributed on multiple parallel circles on the outer spherical surface. Each pair of adjacent inner coils on the same parallel circle corresponds to one outer coil, and the distance between the outer coil and the center of its corresponding two inner coils is the same.

3. The dual-layer metamaterial magnetic induction antenna as described in claim 1, characterized in that, The inner spherical surface has two actual distribution regions located on both sides of the plane where the central magnetic induction loop antenna is located, and the two actual distribution regions have the same inner coil distribution; the outer spherical surface has two actual distribution regions located on both sides of the plane where the central magnetic induction loop antenna is located, and the two actual distribution regions have the same outer coil distribution. The inner layer actual distribution area and the outer layer actual distribution area are both located within the effective space area. The effective space area is the space area enclosed by a conical surface with the center of the sphere as the vertex and the radius of the sphere perpendicular to the plane where the central magnetic induction loop antenna is located as the central axis. The angle between the generatrix of the conical surface and the central circumference is in the range of 50° to 60°.

4. The dual-layer metamaterial magnetic induction antenna as described in any one of claims 1 to 3, characterized in that, The inner coil's coil plane is tangent to the inner spherical surface or perpendicular to the direction of the source magnetic field; the outer coil's coil plane is tangent to the outer spherical surface or perpendicular to the direction of the source magnetic field, and the source magnetic field is the magnetic field generated by the central magnetic induction loop antenna.

5. The dual-layer metamaterial magnetic induction antenna as described in any one of claims 1 to 3, characterized in that, It also includes an inner spherical fixing structure and an outer spherical fixing structure, wherein the inner coil is fixed on the inner spherical fixing structure and the outer coil is fixed on the outer spherical fixing structure.

6. The dual-layer metamaterial magnetic induction antenna as described in claim 5, characterized in that, Both the inner spherical fixing structure and the outer spherical fixing structure are made of plastic.

7. The dual-layer metamaterial magnetic induction antenna as described in any one of claims 1 to 3, characterized in that, Both the inner coil and the outer coil are on circular PCB boards.

8. The dual-layer metamaterial magnetic induction antenna according to any one of claims 1 to 3, characterized in that, Both the inner coil and the outer coil have 1 turn.

9. The dual-layer metamaterial magnetic induction antenna according to any one of claims 1 to 3, characterized in that, The radius of the central magnetic induction loop antenna ranges from 2cm to 3cm, the radius of the inner spherical surface ranges from 4cm to 6cm, and the radius of the outer spherical surface ranges from 6cm to 8cm.

10. A communication device, characterized in that, It includes a dual-layer metamaterial magnetic induction antenna as described in any one of claims 1 to 9.

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